Have tried using StackExchange, was frustrated by the lack of responses. But that got me thinking, is there a site, similar to OSAlt, where we could find (for instance) AGPLv3 alternatives to popular Websites?

All hail the lack of a 140 character limit on Pump.IO! First time I realise migration from Status.Net was not a total loss for me — even if it is still a net loss, due to permissive license, NoSQL usage, loss of Twitter integration and of contextualised conversations references.